The present invention relates to a general-purpose speed-reducing apparatus of high speed reduction ratio. Certain preferred embodiments relate to a speed-reducing apparatus for quietly driving an elevator at a high efficiency.
A speed-reducing apparatus of high reduction ratio was known, for example, in the Japanese Patent Laid-Open Patent Document 2304236.
The prior apparatus is constructed with a crankshaft having a pair of bearing supports which are eccentric to each other. The bearing supports have peripherally spheric bearings of the same size mounted thereon and each of the peripherally spheric bearings has wobbler gear fitted therein as a shaft.
The apparatus of such a type operates as follows. The crankshaft is rotated, the peripherally spheric bearing is revolved to wobble. This makes the first and second gears cycloid-move on the third and fourth gears with which they engage. The output shaft rotation is then reduced at a ratio of tooth number difference of the engaged gears to the rotational frequency of the motor.
The prior speed-reducing apparatus described above has a disadvantage that its cycloid movement involves high engagement slip and low accuracy of the component assembling as engagement is of a curve with a sphere or cylinder. This results in high mechanical noise. It also has another disadvantage in that it is difficult to machine and assemble the many complicated component parts used.
In view of the foregoing, it is an object of the present invention to provide a speed-reducing apparatus having a wobbling rotation plate wherein a speed-reducing mechanism of low mechanical noise is used.
Another object of the present invention is to provide a speed-reducing apparatus having a wobbling rotation plate wherein simple component parts can be easily machined and assembled to a speed-reducing mechanism.
Briefly, the foregoing objects are accomplished in accordance with preferred embodiments of the present invention by a speed-reducing apparatus having a fixed plate and a wobbling rotation plate facing the fixed plate. The fixed plate and the wobbling rotation plate have interengageable portions which effect a reduced speed rotation of the wobbling rotation plate with respect to an input shaft which drives an inclined plate slidably engaging the rotation plate to impart wobbling movement. The fixed plate and wobbling rotation plate are operatively connected together in the axial direction by the interengageable portions thereof.
Upon rotation of the input shaft, an inclined plate carried by the input shaft slidably engages the wobbling rotation plate so that the wobbling rotation plate is sequentially inclined. Drive pin guide holes in the wobbling rotation plate engage with drive pins at the fixed plate so that the wobbling rotation plate is sequentially moved in the input shaft rotation direction at a predetermined reduced rotational speed. A semi-spherical protrusion at the output shaft serves to center the wobbling rotation plate. Thus, the wobbling rotation plate is rotated at a predetermined reduced speed as it is forced into wobbling movement by the input shaft inclined plate. A rotation torque is transmitted from the wobbling rotation plate to output shaft drive pins carried by the output shaft.
Embodiments are also contemplated wherein the wobbling rotation plate and fixed plate are operatively connected to transfer torque by other than interengaging pin and holes. For example, the peripheral edge of the wobbling rotation plate and the fixed plate are provided with respective friction surfaces that engage one another as the wobbling plate rotates around the fixed plate due to the wobbling motion imparted by the input shaft inclined plate slidably engaging the wobbling rotation plate.